Sigmoid Colon Metastasis from Sarcomatoid Renal Cell Carcinoma

Spindle cell proliferations of the sigmoid colon, rectum and anus: a review with emphasis on perineurioma

A wide range of spindle cell proliferations are found uncommonly in the sigmoid colon, rectum and anus. They usually present as polyps, and include reactive lesions and benign and malignant neoplasms which may be primary or metastatic. They are less frequently described in the literature compared to those in the upper gastrointestinal tract, and may be underdiagnosed. The widespread use of sigmoidoscopy in symptomatic patients and bowel cancer screening programmes means that histopathologists must be aware of, and adopt a logical approach to, diagnosing spindle cell proliferations in biopsy and polypectomy specimens. This is particularly relevant given the strong association of some mesenchymal polyps with hereditary cancer syndromes. This review article will focus on perineurioma and the recent debate in relation to its overlap with fibroblastic polyp. The clinical, endoscopic, histological and immunohistochemical features of spindle cell proliferations which should be considered in the differential diagnosis of perineurioma will be discussed. There is also a brief reference to malignant spindle cell tumours of diagnostic importance.

The sub-peritoneal arterial plexus of Sir William Turner

Sir William Turner (1832-1916) was Professor of Anatomy at the University of Edinburgh. His classic paper of 1863 on the anastomoses between the parietal and visceral branches of the abdominal aorta, later known as the sub-peritoneal arterial plexus of Turner, has mostly been forgotten. Located in the retroperitoneum and surrounding the kidneys and other adjacent structures, this plexus is an important route of collateral circulation. In the current paper, we discuss the sub-peritoneal arterial plexus as described by Turner in 1863 and review the literature concerning its potential clinical significance in the kidney, emphasizing its probable role in the metastatic spread of various tumors of abdominal organs and in the continuing viability of the kidney after renal artery occlusion. A biographical sketch of Sir William Turner is also presented.

Metastatic clear cell renal cell carcinoma presenting as multiple colonic polyps

A 92-year-old male presented for routine endoscopic surveillance of his gastrointestinal (GI) tract. He did not have any GI symptoms currently, and the patient had undergone a right nephrectomy for renal cell carcinoma 17 years previously. A lower GI endoscopy revealed polyps in the ascending colon, hepatic flexure, and sigmoid colon (2 polyps). All the polyps were snared and removed in toto. Histological evaluation of all 4 polyps showed similar features. There was expansion of the lamina propria by sheets of clear cells arranged in a nested pattern with a rich vascular network. Immunohistochemistry showed the tumor to be positive for low-molecular-weight cytokeratin, CD10, and vimentin. The features were morphologically and immunophenotypically that of clear cell renal cell carcinoma. This case highlights an extremely unusual presentation of recurrent renal cell carcinoma as multiple, separate colonic polyps 17 years after resection of the primary tumor.